Determination of Precise Optimal Cyclic Strain for Tenogenic Differentiation of Mesenchymal Stem Cells Using a Non-uniform Deformation Field

Although there have been a number of studies regarding tenogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) using uniaxial cyclic stretching stimulation with a homogeneous strain field, it has been difficult to determine the optimal normal strain in the stretch direction for differentiation. We have developed a non-uniform strain field system that in principle would allow determination of the optimal normal strain in a single experiment. As a result, the optimal normal strains of the membrane were clarified as 7.9 and 8.5 % for tenogenic differentiation marker proteins, type I collagen (Col I) and tenascin-C (Tnc), respectively. The non-uniform strain field proposed here represents a powerful tool to determine the optimal normal strain in the stretch direction for hBMSC-to-tenocyte differentiation. Furthermore, we found that the dependence of protein expression level on the normal strain of the membrane differed between proteins, which would be crucial in the field of embryology and regenerative medicine.